A basic assumption of behavioral treatment for chronic pain is that a time-contingent pattern of coping improves functioning, whereas a pain-contingent pattern increases disability. However, despite the fact that many chronic pain treatment programs now address time- vs. pain-contingent patterns of coping behaviors, very few studies have directly tested the effects of these patterns of coping in patients with chronic pain. The primary aim of this study is to use electronic diaries to rigorously evaluate whether patients with chronic pain whose pain coping behaviors show more of a time-contingent pattern demonstrate better adjustment to pain and decreased delay discounting. A sample of 150 patients with chronic low back pain (CLBP: daily pain>6 months in duration) will participate. All subjects will participate in comprehensive evaluation sessions during which we will collect validated measures of psychological distress, physical disability, pain behavior, and delay discounting, before and after an intervening 30-day period. During the 30-day period, 100 randomly selected subjects will complete electronic diaries 3 times daily to measure levels of positive and negative affect, physical functioning, pain coping efficacy, and analgesic intake. Time-contingent coping efforts are those that occur on a regular basis, as measured by the coefficient of variation (variance/Mean) in coping and are not correlated with immediate pain intensity. Data analyses will determine if time-contingent coping relates to diary-based measures of adjustment in CLBP (positive and negative affect, physical functioning, pain coping efficacy, and analgesic intake) and well-validated cross-sectional measures of psychological distress, physical disability, pain behavior, and delay discounting. Lagged within-day assessments will allow us to calculate the extent that coping efforts follow increased pain at the previous occasion within the day. Analyses will assess subjects' general health, pain diagnosis, levels of pain, opioid use, quality of social support, small and major stressors to control for factors that may influence pain coping patterns. If the current study finds that diary-based measures of time-contingent and pain-contingent coping patterns are related to measures of adjustment to pain, then clinicians may wish to incorporate such diaries into their treatment protocols. If a time-contingent pattern of coping is related to delay discounting, then future studies might explore the effects of interventions designed to increase how patients value delayed outcomes. This study may lead to major advances in our understanding of CLBP, enlarge our clinical armaments for effectively treating CLBP, and may reduce the high societal costs associated with this painful disorder.